High-speed safety cutter head



Apr! 26 1927' L. T. MEDHOLDT HIGH SPEED SAFETY CUTTER HEAD Filed Fb. 24, 1925 at'speeds much in excess of 3600 R. P. M.

as to resist the tendency of centrifugal force latt earse stares earner entice,

LOUIS T. MEDHOLDT, 0F ROCKFORD, ILI2INOIS,

WORKS, OF ROCKFORD, ILLINOIS, A CORPORATION OF ILLINOIS.

HIGH-SPEED SAFETY CUTTER nnan Application filed February 24, 1925. Serial No. 11,059.

This invention relates tocutter headsfor use on straight or variety molders. The common form of cutter head used-on such machines carries a plurality of knives secured to the outer sides of the cutter head by means of bolts. In the rotation of the cutter head centrifugal force and the pressure due to contact away from the cutter head, these forces being resisted by the before-mentioned. bolts,

At present the-ordinary speed of operation of such machines is 8600 revolutions the cutter head per minute, but there is an insistent demand for much higher speed. Cutter headshaving securing means of the type alluded to can not be safely rotated Highspeed operation requires, first, that the cutter head he as small in diameter as possible so as to lessen centrifugal force and reduce as much as possible the necessity for accurate balancing; second, that the strain-be taken off the knife-securing bolts; and third, that the knives be supported as close to their cutting edges as possible so and the 'pressureof the knives against the work to swing or from the cutter heat.

It is the object of this invention, generally stated, to produce a cutter head of such construction that it may be safely operated at speeds twice as great as those now employed and at the same time render it possiblefor manufacturers to continue to use their present'equipment of cutter knives.

Another object of the invention is to provide a head of sectional or built-up construction so designedt-hat the user may build up a head of desired length with a minimum embodying the features of my numberof pieces. 7 In the accompanying drawing, Figure 1 is a side view of one form of cutter head invention. Fig. 2 is a section on line 2-2 of Fig. 1. Fig. 3 is a detail view of an expansible bushing or sleeve.

Fig. 4 is a sectional plan view of thecut 0 'ter head taken on line 4-4 of Fig. 1. a

Fig. 5 is a detail end viewof one of the side sections.

of the knife with the work tend to swing or bend the knives" bend the knives away side sections that by tightening Fig. 6 is an edge View of one of the end sections. I

Big. 7 s an nner side view of one of the GHClSGCtlOIIS.

Fig. ring.

tion are adapted for use on the top hori-,' zontal spindle, :the bottom hor zontal spin assrenon TO MArTIson ivrAcHfNn S is a detail view of acontractible Cutter heads embodying the present invendie, the right hand vertical side'spindle, and

the left hand vertical side spindle. The part A in the drawing may be taken resent any one of said spindlesorfarbors.

As hereinbc-fore stated, the cutter "head is of sectional or built-up construction. comprises four side sectionsl, two endsections 2,".and means for securing said sec-Q tions together.

As 'shown iirFig. 5, each side section lhas a generallyflat inner side, the outer side being rounded to conform to. the radius ofthe cutter cutter headshal-l havea substantiallycy lindrical form. The ends of the side sections are beveled, as shown at3 in F ig.12.'

Each of the end sections 2 has a flat outer side. On the inner side of theend sections are formed four beveled surfaces 4 as shown in Figs. 2, 6 and 7, to engage the correspondinglybeveled surface 3 of the 1. The beveled orequivalent surfaces 4 are arranged in the form of a rectangle or square soas tohold the four side sections 1 in the form of a, hollow square. The circumference of the end sections 2 is the same as that of the cylinder defined by the outer surfaces of the side sections 1. v v

The side sections 1 and the end sections 2' head so that the are rigidly secured together by means of" I four bolts 5. adapted to extend through openings 6 in the end sections 2.. The heads 7 of said bolts are tapered upon their inner sides to conform to the taperedouter ends of the openings 6. The nuts 8 of said bolts have tapered inner form to thetapered outer ends of the openings 6 in the end section. It will be seen upthe nuts 8 the four side sections 1 and a cylindrical head.

provided to permit of sides which also con the two ,end sections 2 i may be tightly. clamped together to form.

assembling cutter heads of desired lengths.

' The sleeve is preferably long enough to be used with heads of various lengths, filling collars being placed under the nut 13 in the case of short heads.

Each of the bolts 5 extends through, a groove 9 (Fig. 5) in the inner side of one of the side sections 1. The bolts thus serve to locate the side sections properly in the operation of assembling the cutter head, and hence obviate the possibility of the operator failing to secure the side sections in proper position through inadvertence or carelessness.

The means for securing the cutter head on the spindle A includes a sleeve 10 adapted to fit upon the spindle Aand having at one end a tapering shoulder 11'to engage a correspondingly tapered central opening 12 in the adjacent end section 2. The sleeve 10 is long enough to extend through the cutter head and project beyond one end thereof sufficiently far to receive a locking nut 13. Below the nut 13 is placed a self-centering clamp ring 14 which is beveled upon its outer side to correspond with the beveled opening 12 in the outer end section 2. The ring 14: surrounds the sleeve 10 and is split, as shown at 15in Fig; 8, so that it may be contracted upon the sleeve 10. The latter is also slotted atone side, as shown at 16 in Figs. 2 and 3.- Itwill be seen that when the nut 13 is tightened up, the pressure of the tapered surface 11. on said sleeve against the tapered wall of the opening 12 in the adjacent end section 2 will cause that end of the sleeve to be contracted into clamping engagement with the spindle A; and that the pressure of the ring 14 against the tapered wall of the opening 12 in the other section 2 will cause said ring to be contracted into clamping engagement with the sleeve 10, thus causing the latter to be contracted into engagement with the spindle A, and also giving additional pressure against end plates or discs.

If desired, the sleeve 10 may be slotted all the way through, as indicated in Fig. 3, except at one end, so that the driving pin used in connection with some spindles may extend through said sleeve.

As shown in Figs. 1 and2, the nut 13 is slotted at 17 so that it may be contracted by means of a screw 18 and thus securely looked upon the sleeve 10.

The knives may be of anysuitable form, but, as hereinbefore stated, the cutter head has been so ted knives with which most manufacturers are equipped may be employed. The knives are indicated atB and B. I

shown in Fig. 5, one end of each side section 1 is cut away or shortened, thus proriding aslot 119 trig. 1) int-qwhich a cutter knife I bolt 20 extends I together,

b tween the adjacent side sections tween adjacent side sections against which it lies by any suitable means,

a bolt 20' adapted to exas, for example, tend through the conventional slot 6 (Fig.

2) of the knife, said bolt having a head 21 j lying at the inner side of the knife. The through a longitudinal slot- 22 formed in the side section. Said slot is widened or countersunk as at 23 so that the nut 24 on the outer end of the bolt 20 shall not project beyond the periphery of the cutter head.

The diameter of the spindle A is ordinarily one and thirteen-siXteenths inches. The cutting diameter of prior styles of cutter heads for spindles of that size is usually siX and one-half inches. The present ins vention permits of reducing the cutting diameter of the cutter head to live and one-f eighth inches on a spindle one and thirteenslxteenths inches in diameter and in th1s proportion up or down thecscale of spindle" sizes.

It will be seen that the cutter head construction' herein described is especially well adapted for high speeds. The knives lie within the cutter head, the stresses due to centrifugal force and the cutting reaction being borneby' the side'sections 1, which.

are amply strong to carry the load ims posed upon them. The bolts 20 have a relatively light duty to perform. As indicated in Fig. '4, the knives are supported or backed up relatively close' to their cutting edges, lessening the tendency of the cutting. reaction and centrifugal force to spring or bend the knives. These several features, in conjunction with the reduction in diameter,

.llltllie for safe operation at very high speeds.

It will be obvious that the sectional method herein disclosed of building up cutter heads may be employed in making two-sided and three-sided heads, the end sections 2 hav ng a number of beveled surfaces 4' corresponding to the number of side sections.

If desired, the cutter head may be located upon and secured to the spindle by means of the form of nutshown in my copending' application Serial No. 738,116, filed Septeinbcr 17, 1924. i

I claim as my invention: 1. A sectional cutter head for wood-workin machines having, in" combination,.two end sections and a pluralityof side sections, said side sections having beveled ends and the end sections having upon their inner devised that the standard slotsides correspondingly beveled surfaces similar in number to the number of side sections;

bolts extending through said end sections to clamp the end sections and side sections each side section havingup'on its inner side a groove through the bolts este'nds, s pae being provided bewhich one of to form .liiiif- I of side sections,

receiving slots; knives lying in said slots, each of said S] de sections being longltudinally slotted, and a bolt extending through each of the last mentioned slots and through one receiving slots; knives lying insaid slots;

and means to secure the knives in said slots.

A sectional cutter head having, in combination, two end sections and a plurality of side sections; bolts extending through said end sections to clamp the end sections and side sections together, each side section having upon its inner side a groove through which one of the bolts extends, space being provided between adjacent side sections to form knife-receiving slots; knives lying in said slots; and means to secure the knives in said slots.

4. A sectional cutter bination, two end sections and a plurality of side sections, each side section having a substantially flat inner side and an outer side rounded to produce with the other side sections a cylindrical head; bolts extending through said end sections to clamp the end sections and side sections together, each side section having upon its inner side a groove through which one of the bolts extends, and a knife clamped against the inner side of each side section.

5. A sectional cutter head having, in combination, two end sections and a plurality said side sections having beveled ends and the end sections having upon their tions to form knife-rec head having, in com beveled their adjacent sides correspondingly beveled inner sides correspondingly beveled surfaces similar in number to the number of side sections; means to clamp the .end sections and side sections together; space being provided between adjacent side seceiving slots; knives lying in said slots; and means to hold the knives against the inner sides of the side sections.

6. A sectional cutter head having, in combination, two end sections and a plurality of side sections; said end sections toclamp the end sections and side sections together; space being provided between adjacent side sections to form knife-receiving slots; knives lying in said siots; and means to hold said knives against the inner sides of the side sections.

In a cutter head of the character described, the combination of a pair of end sections, a plurality of side sections having end portions interengaging with said end sections, knives clamped to the inner sides of said side sections, and means to clamp the end sections to the side sections in an axial direction.

8. In a cutter head of the character described, the combination of a pair of end bolts extending through sections, a plurality of side sections having end portions interengaging with said end sections, knives clamped to the inner sides of said side sections, and means to clamp the end sections to the side sections.

9. In a cutter head of the character described,the combination of a pair of end sections, a plurality of'side sections having ends, the end sections having upon surfaces, knives clamped against the inner sides of the side sections and bolts extending through said end sections to clamp the end sections and side sections together.

In testimony whereof, I have hereunto affixed my signature.

LOUIS T. MEDHOLDT. 

